Deputy Attorney General Rod Rosenstein will be brought before the heads of the House Judiciary and Oversight Committees Wednesday, Oct. 24, wrapping up a series of closed-door interviews in recent weeks.

Rosenstein's testimony comes amid a push from Republicans to expose what they believe is Justice Department bias and active attempts to undermine President Donald Trump.

That GOP-led effort was largely frustrated this week as the House Judiciary-Oversight task force heard from three witnesses connected to the Federal Bureau of Investigation's 2016 probe into alleged ties between the Trump presidential campaign and Russia, which evolved into the special counsel investigation.

NELLIE OHR AND FUSION GPS

On Friday, members of the task force heard from Nellie Ohr, a Russia expert and wife of a former top Justice Department official Bruce Ohr. Mrs. Ohr was hired in 2016 by the political intelligence firm Fusion GPS to compile a dossier on then-candidate Donald Trump and his alleged ties to Russia.

The congressional task force insisted on hearing from Ohr on suspicions that she acted as a backchannel between Fusion GPS and the Justice Department, which used the dossier to justify surveillance on at least one Trump campaign associate.

Congressmen described Nellie Ohr as cooperative. During more than four hours of questions, she gave her account of how and why she was hired as an independent contractor for Fusion GPS but provided few details about the information she may have passed on to her husband, Bruce Ohr, at the Justice Department. She and her lawyer maintained those details were protected under spousal privilege.

"Today's interview really didn't produce anything of value," said Rep. Mark Meadows, R-N.C. "Candidly, the responses today did not help us in the spirit of transparency to find any more of what happened or may have happened during those critical times when she was working with Fusion GPS."

The Trump dossier would have gotten to the FBI without her, Meadows told Sinclair Broadcast Group. "There were multiple people working on getting the dossier to the FBI. So it's not just her as the only conduit," he said.

GLENN SIMPSON AND CHRISTOPHER STEELE

Another suspected "conduit" was Fusion GPS founder Glenn Simpson, who lawmakers tried to interview earlier this week. It was another dead end.

Simpson asserted his Fifth Amendment right and declined to answer the committees' questions. His lawyer issued a statement denouncing Republicans' conduct, saying, "This committee would make Sen. Joseph McCarthy proud."

Simpsons' silence frustrated Republicans like Meadows who asserted "it shows that potentially a crime was committed."

Simpson was responsible for hiring Christopher Steele, a former British spy and trusted FBI informant, who authored the dossier on Trump and Russia. The work was paid for by a law firm representing the Hillary Clinton campaign and Democratic Party.

Simpson was in contact with Nellie Ohr's husband, Bruce Ohr on multiple occasions in 2016, according to documents released by the congressional task force. In Dec. 2016, Simpson met Ohr and gave him a thumb drive with information purporting to connect members of Trump's inner circle to Russia.

Ohr also communicated with Steele while the ex-spy was producing the Trump dossier. Email records show Steele contacted Ohr to discuss the status of Russian oligarch and aluminum magnate Oleg Deripaska and Russian operative Maria Butina.

Butina was indicted earlier this year as part of Special Counsel Robert Mueller's investigation. She faces charges of acting as a foreign agent and conspiring to influence U.S. politicians. Deripaska was allegedly in contact with Trump campaign manager Paul Manafort during the 2016 election. The two had previous business dealings. Manafort was later charged for multiple financial crimes. On Friday, some of those criminal charges were dropped in light of Manafort's cooperation with Mueller.

Bruce Ohr continues to work at the Justice Department and has been the target of President Trump's ire. On Tuesday, Trump referred to Nellie Ohr as a "Pawn" in and questioned why Bruce Ohr had not yet been fired from DOJ.

Bruce Ohr was demoted earlier this year from a high-ranking position as associate deputy attorney general and director of DOJ's Organized Crime Drug Enforcement Task Force, where he specialized in Russian organized crime and money laundering.

Nellie Ohr also specialized in Russian organized crime, a fact that Democratic Rep. Raja Krishnamoorthi of Illinois argued is relevant to Fusion GPS' decision to hire her in its investigation of Donald Trump.

"This is not necessarily new information but it goes into detail about the ties between Donald Trump and the Russians," he said, arguing Congress should be focusing its energy on those connections. "This is something that's very serious and expansive. That's why she was originally retained."

Krishnamoorthi, the only Democratic congressman to attend the Friday briefing, dismissed his colleagues' suspicions that Mrs. Ohr was brought in as part of a politically motivated effort funnel derogatory information about Trump through her husband to the FBI.

"All along there's been kind of a conspiracy that's been spun about what's happening," he said. "It's been a big waste of time. I haven't seen anything that leads me to believe there's a conspiracy at DOJ or FBI or anything untoward happened."

ROD ROSENSTEIN AGREES TO CLASSIFIED BRIEFING

However, outspoken Republicans on the Judiciary and Oversight Committees have grown increasingly convinced of Justice Department efforts to undermine President Trump, specifically related to Deputy Attorney General Rod Rosenstein.

On Thursday, the congressional task force interviewed former Justice Department general counsel James Baker for the second time this month. In his first appearance, Baker reportedly provided lawmakers with "explosive" new information about political bias at the Justice Department which raised questions about Rosenstein's relationship with President Trump.

"It's time that Rod Rosenstein steps down," Meadows told reporters Thursday after interviewing Baker. "He should do so immediately and in doing that I think it would serve the country well, it would serve this president well."

Those reports nearly cost Rosenstein his job. He was prepared to resign in late September, but Trump decided to leave the deputy attorney general in his post.

Earlier this week, Republicans threatened to subpoena Rosenstein after he refused to appear before the joint Judiciary-Oversight task force. On Friday, Rosenstein agreed to testify in a classified setting with only the Republican chairmen and Democratic ranking members of the two committees.

Meadows called the arrangement "weakness" on the part of Congress to hold Rosenstein accountable.

Rep. Matt Gaetz, R-Fla., equated the classified interview with "some little game of paddy cake with the committee chairmen and the ranking members." He said there would be no transcript of the interview that could be shared with other members of the committee or the public.

"This is how you conduct oversight if you don't really want to find the truth," he charged.